Main content area

Advanced exergy analysis of recompression supercritical CO2 cycle

Mohammadi, Z., Fallah, M., Mahmoudi, S.M. Seyed
Energy 2019 v.178 pp. 631-643
carbon dioxide, compressors, enthalpy, entropy, exergy
Conventional and advanced exergy analysis of a recompression supercritical CO2 cycle was investigated in this study. The first and second splitting levels of exergy destruction are calculated to determine the real potential of enhancement for the S-CO2 cycle performance. The thermodynamic cycle method of advanced exergy analysis is applied in the present work to reveal the endogenous, exogenous, avoidable, unavoidable, avoidable endogenous, unavoidable endogenous, avoidable exogenous, and unavoidable exogenous exergy destruction for each system component. The overall exergy efficiency for the system are determined as 16.63% and 17.13% under real and unavoidable conditions, respectively. Based on the total avoidable exergy destruction rate, the maximum improvement potential for the system is 106.855 MW (about 50% of the total exergy destruction), and of this avoidable value, 34.59% is endogenous, and 65.41% is exogenous. It is also revealed that, for improving the overall system performance, the priority order of components obtained by the conventional exergy analysis is different from that achieved by the advanced exergy analysis. The former suggests this order as: the reactor, the pre-cooler, the LTR, the HTR and the turbine, while the latter recommends the priority as the HTR, the turbine, and the main compressor. The results also indicate that the reactor has the least potential for improvement despite its highest exergy destruction.